Why does nobody bring up setting valves on a cold engine anymore?

Had a long chat with a retired diesel guy named Walt at a truck stop outside Amarillo about a month back, and he asked me how I set the overhead on my old 12 valve. I said I always do it hot, just like the book says. He laughed and said he ran a fleet of 40 trucks for 22 years and set every one of them stone cold on Saturday mornings, then checked a few hot to be sure the gap closed up right. That got under my skin, so I tried it on my own rig, and the cold method actually let me hear a loose rocker before it started hammering. Now I do a cold pass first, write down the numbers on a notepad, then do a hot pass to confirm nothing moved. The old manuals in Walt's day even had a cold spec, but you hardly see that printed now. Any of you still setting the overhead cold first, or did everyone move on to hot only?